"I can die happy, this is the only reason I got into politics," Senator Hinch said of the announcement.

He said any new legislation should be known as 'Daniel's Law' — named after Queensland 13-year-old Daniel Morcombe, who was abducted and murdered by sex offender Brett Cowan in 2003.

While welcoming the plan, the Justice Party representative said it should go further and include offenders' addresses.

"If you rape a child, you lose your civil rights," he said.

Daniel Morcombe's mother, Denise Morcombe, said the register was a "fantastic" plan.

Ms Morcombe said the register would help parents and carers better protect their children by allowing people to know how many registered offenders are in their area.

She said it would also help protect single mothers who may be trying to find a new partner online.

"If they meet someone, they'll be able to put that person's name into the website and see if this person is a serious offender or not."

But child safety advocate Hetty Johnson from Bravehearts suggested the proposal was more about winning votes than protecting children.

"This will never be implemented, I just don't believe that all the states and territories will come on board," she said.

"It's a bit of a chest-beating exercise that will lead to nothing."

Ms Johnson warned that only 10 per cent of child sex offenders were known to authorities.

Concerns raised over possibility of vigilante attacks

The Australian Institute of Criminology, which reports to the Home Affairs Minister, last year published a research paper that found "the effectiveness of public sex offender registries [is] mixed".

"While public sex offender registries may have a small general deterrent effect on first-time offenders, they do not reduce recidivism," the authors wrote.

Federal Labor said it was important any changes were "evidence-based and effective".

"Mr Dutton must show how this makes children safer," shadow attorney-general Mark Dreyfus said.

"When this was raised a few years ago, then-prime minister [Tony] Abbott rejected it.

"It would be good to know what has changed since then."

President of the Law Council of Australia, Arthur Moses SC, said while he supported the idea of a register in principle, he believed names should only be added at the discretion of a sentencing court, rather than on an automatic basis.

He also said he was concerned about potential vigilante attacks on listed offenders.

"We need to make sure people do not commit offences as they potentially engage in some form of retribution in relation to these offenders," Mr Moses said.

He said the establishment of similar registers in the United States had shown they "do not necessarily prevent sex offending in the general community".

In her resignation from politics, Kelly O'Dwyer said she feared another miscarriage in Canberra, far from home. Her announcement is shocking for more than just party-political reasons, writes Emma A. Jane.